1. Field of Invention
The invention relates to a powder force-operated setting tool including a piston guide having a bore a cartridge-receiving seat, and a discharge channel, with the cartridge-receiving seat and the discharge channel opening into the guide bore, and a drive piston displaceable in the guide bore.
2. Description of the Prior Art
When fastening elements are driven with a setting device into materials having different hardness and strength, the resistance, which has to be overcome, varies. There is therefore a need for adapting the driving-in power of the setting tool to local conditions. EP-0 330 950 discloses a setting tool in which propellant charges of uniform hardness are used. The different driving-in powers is controlled by a power regulating device provided on the equipment. The piston guide of this known setting equipment a bore, in which a driving piston reciprocates parallel to the setting direction. A cartridge-receiving seat and a discharge channel, the cross-section of which can be changed by a regulating pin, open into the guide bore. In this known setting tool, since the discharge channel opens immediately after the driving piston is started by the ignition of a cartridge, the pressure of the driving gas partially decreases before it has built up completely.
It is therefore an object of the present invention to provide a powder force-operated setting tool, which can be manufactured economically and for which a decrease in the pressure of the driving gas immediately after the driving piston is started is prevented, and the discharged channel opens only when the driving piston has been shifted in the setting direction a certain amount.